Solid state variable direction of view endoscope

ABSTRACT

An endoscope with a wide angle lens that comprises an optical axis that is angularly offset from a longitudinal axis of the endoscope such that the optical axis resides at an angle greater than zero degrees to the longitudinal axis. The wide angle lens system simultaneously gathers an endoscopic image field at least spanning the longitudinal axis and an angle greater than ninety degrees to the longitudinal axis. The endoscope further includes an imager comprising an imaging surface area that receives at least a portion of endoscopic image transmitted by the wide angle lens system and produces output signals corresponding to the endoscopic image field and image forming circuitry that receives the output signal and produces an image signal.

FIELD OF THE INVENTION

The present invention relates to variable direction of view endoscopes,in particular, variable direction of view endoscopes incorporating solidstate imagers.

BACKGROUND OF THE INVENTION

Variable direction of view endoscopes allow the user to change theendoscopic viewing direction without having to change the position ofthe endoscope itself. Such endoscopes are useful when the user wants tosee structures which are beside or behind the tip of the endoscope butcan not easily move the endoscope shaft because of anatomicalconstraints or constraints imposed by other surgical instruments in theoperative field.

Variable direction endoscopy is desirable because it affords surgeonsgreater flexibility in their procedural approach. Increased viewingmobility improves the quality of diagnoses, as in cystoscopy forexample, where a typical diagnostic screening involves inspecting theinterior surface of the bladder for lesions or tumors. The ability tolook laterally and retrograde is important when doing this type ofdiagnosis because it makes it possible to visually cover the entirebladder surface, including the entrance region near the bladder neck. Inear-nose-throat and neurosurgical procedures, variable viewing isdesired because the procedures are delicate, and the entrance ports aresmall. It is therefore not possible to manipulate the endoscopesignificantly without injuring the patient. The ability to look sidewaysand backwards is important however during and after tumor resection whenit is necessary to keep track of tumor fragments, which if not caughtcan nucleate new tumors. Laparoscopy, another surgical discipline,imposes fewer maneuvering constraints but still benefits markedly fromvariable direction viewing because it allows surgeons to get betterobservation angles during a procedure and increases diagnosticcapabilities. Also, because of the greater viewing versatility, variabledirection of view endoscopes can minimize conflicts with other tools andcan simplify surgical planning by their ability to achieve standardviewing angles from nonstandard positions, allowing the surgeon to keepthe endoscope “off to the side” but still get the desired view.

A fundamental feature of variable direction endoscopy is that itgenerally makes it possible for surgeons to eliminate “blind movements.”A blind movement is the process of moving an instrument inside a patientwithout being able to see where the instrument is heading. This canoccur when it is necessary to advance a fixed-angle side viewingendoscope in its length direction without being able to see what isahead of the scope, or when a surgical tool has to be manipulated at theboundary of the endoscopic field of view.

Many known variable direction of view endoscopes also have drawbacks.First, these scopes use a movable image sensor or optical element at thetip of the scope to vary the viewing direction. Because of these movingparts, fabricating variable direction of view scopes is complicated andcostly, and such scopes are less robust than traditional fixed-anglescopes. Also, they often deliver inferior illumination and imagequality.

These scopes, both rigid and flexible tip endoscopes, also subject theuser to disorientation. As the endoscopic line of sight is changed, theuser faces two difficulties. The first is keeping track of where theendoscope is “looking.” With a rigid fixed-angle endoscope it isrelatively easy for the user to extrapolate the endoscopic viewingdirection from the position of the endoscope shaft. This is not the casewhen the viewing direction is regularly changed relative to thelongitudinal axis of the endoscope; the user quickly loses track ofspatial orientation within the anatomy being observed. The seconddifficulty is keeping track of what is “up” in the endoscopic image.Depending on the view-changing mechanism, the image will rotate relativeto the surroundings, and the user frequently loses orientation. Thisdisorientation is often not correctable, especially in variabledirection of view scopes which have distal imagers and no facility forchanging image orientation.

Given the difficulties of variable direction endoscopes, it is commonfor surgeons to utilize rigid endoscopes with fixed viewing angles.Surgeons rely heavily on knowing that a certain endoscope provides a 30or 45 degree viewing angle. This preference for using multiple fixedangle endoscopes is due in part to the fact that a surgeon knows thatfor a particular endoscope they can dependably know what the anatomyshould look like. FIGS. 1A, 1B, 1C and 1D show the distal ends of fourcommercially available endoscopes 10, 20, 30, 40 with the most commonlyused viewing directions (view vectors) 50 corresponding to angularoffsets from the longitudinal endoscope axis 60 of 0, 30, 45, and 70degrees. Different surgical procedures typically require endoscopes ofmost of these angles with specific emphasis on one of them, often the 30degree endoscope because it provides both a good forward view and acertain amount of lateral viewing. However, in most procedures, such asear-nose-throat, bladder, orthopedic, brain, and abdominal procedures,lateral and partial retroviewing is beneficial and can be vital.Unfortunately surgeons often try to make due with only one or two scopesbecause changing the endoscope mid procedure is cumbersome (both lightand camera cables have to be disconnected and reconnected), timeconsuming, and sometimes dangerous. Also, inserting off-angle endoscopescan be dangerous because they are not “looking” in the direction theyare being inserted. This is a problem in neurosurgery, where surgeonsoften will not use 45- or 70-degree endoscopes because they are afraidof blindly thrusting the endoscope into delicate tissue.

Several designs have been proposed that provide solid state variabledirection of view endoscopes to reduce or eliminate the number of movingparts. U.S. Pat. Nos. 5,185,667 and 5,313,306 disclose using a fish-eyelens that provide a hemispherical field of view, i.e. the lens providesa wide angle image that provides variable viewing in both the x and ydirections. U.S. Pat. No. 6,449,103 discloses the use of an endoscopewith a catadioptric system. U.S. Pat. No. 5,800,341 discloses anendoscope with charged coupled devices (CCDs) forming a circumferentialband about the distal portion of the endoscope or CCDs coveringsubstantially all of the outer side wall of the shaft adjacent to thedistal end. U.S. Pat. No. 5,954,634 discloses the use of an image sensorat the proximal end of the endoscope that can move in a directionperpendicularly to the optical axis to enable selected portions of theimage field to be viewed. However, these solutions can be considereddeficient because they either provide poor resolution compared to astandard 70 degree field of view system, are overly complex and notfeasible to manufacture, do not provide retrograde viewing, i.e. viewingat an angle greater than 90 degrees relative to the axis of theendoscope in the distal direction, or still incorporate overly complexmotion.

What is desired, therefore, is variable direction of view endoscope thatcan provide a feasible design and reduce the number of moving parts. Itis further desired to provide an endoscope that can also provide forwardand retrograde viewing. It is still further desired to provide anendoscopic system that enables a surgeon to utilize reliable standardendoscopic viewing angles and at the same time provide an overall fieldof view that encompasses the viewing range.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide anendoscope with a wide angle lens system that comprises an optical axisthat is angularly offset from a longitudinal axis of the endoscope suchthat the optical axis resides at an angle greater than zero degrees tothe longitudinal axis. The wide angle lens system simultaneously gathersan endoscopic image field at least spanning the longitudinal axis and anangle greater than ninety degrees to the longitudinal axis. Theendoscope further comprises an imager comprising an imaging surface areathat receives at least a portion of endoscopic image transmitted by thewide angle lens system and produces output signals corresponding to theendoscopic image field and image forming circuitry that receives theoutput signal and produces an image signal. It is preferable that theimaging surface area is rectangular with the longitudinal dimension ofthe imagining surface area corresponding to the longitudinal dimensionof the endoscopic image field.

It is another object of the invention to provide an endoscopic systemwith image selecting circuitry that receives the image signal andproduces a region of interest signal that corresponds to a region ofinterest field that is less than the endoscopic image field. The regionof interest field can correspond to standard endoscopic viewing anglesof zero, thirty, forty-five, and seventy degrees. The endoscopic systemcan further comprise image control circuitry that receives a region ofinterest field selection from a user input and produces a field controlsignal identifying the region of interest field. The image selectingcircuitry receives the field control signal and produces the region ofinterest signal in accordance with the field control signal. The imageselecting circuitry can rotate the image formed by the region ofinterest signal about the axis of the viewing angle in order toalleviate disorientation by the user when switching between standardendoscopic viewing angles.

The user input can enable a user to select at least one preset standardendoscopic viewing angle and instructs the image control circuitry togenerate a field control signal in accordance with that selection. Theuser input can further enable a user to select a progressive adjustmentand produces an adjustment signal that incrementally alters the regionof interest.

The endoscopic system can still further comprise video processingcircuitry that generates video signals on the basis of the image signaland/or region of interest video signal and output a all image videosignal or region of interest video signal respectively to a display. Thevideo processing circuitry can also provide a combined video signalcomprising a first frame displaying the region of interest video signaland a second frame displaying the all image video signal.

It is yet another object of the present invention for the endoscope tocomprise a transmission system that redistributed the angle of incidenceof the image rays gathered from the endoscopic field of view on to theimage surface area in order to even out the information density accrossthe surface area. This can be provided by a lens system thatredistributes substantially the entire endoscopic image field in thelongitudinal direction to correspond to the imaging surface area.Preferably this lens system is an f-theta lens system. Other objects ofthe invention and its particular features and advantages will becomemore apparent from consideration of the following drawings andaccompanying description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-D is a depiction of standard fixed angle endoscopic systems.

FIG. 2A is cross-section of the distal end of the endoscope of thepresent invention along the longitudinal axis.

FIG. 2B is a depiction of the image sensor of the endoscope of thepresent invention relative to the endoscopic field of view.

FIG. 2C is a schematic of the circuitry for the endoscopic system of thepresent invention that provides for image processing.

FIG. 3A is a depiction of information distribution upon an image sensorfrom a wide angle lens without image correction.

FIG. 3B is a depiction of information distribution upon an image sensorfrom a wide angle lens with image correction.

FIG. 4A is a depiction of a display generated by the endoscopic systemof the present invention.

FIG. 4B is a depiction of another display generated by the endoscopicsystem of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates the invention by way ofexample, not by way of limitation of the principles of the invention.This description will enable one skilled in the art to make and use theinvention, and describes several embodiments, adaptations, variations,alternatives and uses of the invention, including what is presentlybelieved to be the best mode of carrying out the invention.

FIGS. 2A and 2B depict a preferred embodiment of the present invention.FIG. 2A, depicts a distal tip 10 of an endoscope with a longitudinalaxis 60, a viewing window 70, a wide angle lens system 165 with opticalcenter 160 and a transmission system 150. The optical center 160 isangularly offset from the longitudinal axis 60 of the endoscope 10 andcovers a viewing range 130 of 160 degrees from −45 to +115 degreesrelative to the longitudinal axis. From this configuration, the wideangle lens system 165 simultaneously gathers an endoscopic image field130 that spans the longitudinal axis and an angle greater than ninetydegrees to the longitudinal axis. As a result, the simultaneous imagefield gathered by the endoscope provides both forward and retrogradeimaging. Providing a variable view endoscope that spans this range isbeneficial because it enables a user to view objects that reside infront of the endoscope and behind the standard fields of view forendoscopes. This improves the ability of a user to safely operate andhandle the device in the body cavity. Further by incorporating a wideangle lens with an optical center that is angularly offset relative tothe longitudinal axis, the endoscope will be able to more accuratelymimic the viewing capabilities and function of a fixed angle endoscope.As discussed in more detail below, while wide angle lenses arebeneficial in that they can increase the overall field of view, onedeficiency is that they tend to provide an uneven informationdistribution over the overall field of view, i.e. the resolution ofimages obtained at angles further away from the optical axis will bediminished. As a result, a wide angle lens with an optical center thatis angularly offset will enable the endoscope to produce higherresolution images at angles that correspond to standard fixed angleendoscopes. This will improve the willingness of surgeons to adopt anduse variable view endoscopes.

The image field gathered by wide angle lens system 165 is conveyed totransmission system 150, which will be discussed in more detail below.Transmission system 150 in turn conveys the wide angle field of view toan image sensor that comprises image surface area 170. Image surfacearea 170 is formed by a plurality of pixels that gather light images andconvert the images to output signals. Image surface area 170 ispreferably rectangularly shaped with a longitudinal dimension that isgreater than its lateral dimension, but can also be a variety ofdifferent shapes, such as square, circular or oval. Also, it ispreferable that the image surface area 170 has an HD aspect ratio of16:9. Since a wide-angle lens system can provide uneven informationdistribution, without correction an HD image sensor enables the crowdedinformation regions to be captured and displayed on a monitor. As shownin FIG. 2 b, image surface area 170 partially captures field 130. It ispreferable that the longitudinal dimension of image surface area 170substantially correspond to the entire longitudinal dimension of field130. This enables the endoscopic system to provide the user with animage or a range of regions of interest that span the field of view ofthe endoscope. However, image surface area 170 only captures a portionof the lateral dimension of field 130. The lateral dimension of area 170can be chosen such that the distortion of an image laterally is minimaland not detected by the human eye. Further, by limiting the lateraldimension of the sensor, the cross-sectional area of the endoscope canbe more efficiently used. For instance, the lateral dimension of thewide angle lens can be reduced and consequently reduce the overall sizeof the endoscope. Also, the area of the field of view not captured bythe sensor can be used carry a fiber optic illumination system.

FIG. 2 b also depicts specific regions of interest (ROIs) at 0, 30, 45and 70 degrees which can selected by a user over a range 190 and isdiscussed in more detail below. A region of interest is an image areaformed on image surface area 170 that is a subset of the overall fieldof view captured by the sensor. The center of the area of the ROIcorresponds to a selected longitudinal viewing angle chosen by a user.The overall area of the ROI can correspond to the field of viewtypically provided by a fixed angled endoscope for that same angle.Alternative, the overall area of the ROI can be chosen to provide aminimal distortion variation across the overall area. This can beachieved by providing image selecting circuitry that forms a region ofinterest signal based on a predetermined set of sensor pixels.Alternatively, this can be achieved by providing an image selectingcircuitry that measures the degree of variance of an image signal forpixels that encompass the viewing angle and selects an area of the ROIbased on a distortion tolerance. Still further, the overall area of theROI can be chosen such that the field encompassed by a viewing angle atleast partially overlaps with an adjacent standard viewing angle, suchas 30 and 45 degrees. ROIs that are sized to overlap with adjacentviewing angles will assist a user in maintaining orientation in theevent that a viewing angle is changed.

As shown in FIG. 2C, image sensor 175 produces output signals 212 thatcorrespond to the endoscopic image field. Image forming circuitry 200receives the output signals and converts the signals in to image signals214. Image signals 214 can be received by image selecting circuitry 202,which utilizes this signal to produce a region of interest signal 216.As discussed above, image selecting circuitry 202 forms ROI signal 216by selecting the portions of the image signal 214 that correspond to thepixels of sensor 170 that surround a particular viewing angle within agiven area. FIG. 2C also shows that the endoscopic system also comprisesa user input 206, from which a user can select a region of interestviewing angle. When a user selects a region of interest viewing angle,input 206 transmits a region of interest field selection 218 that isreceived by image control circuitry 204. Image control circuitry 204 inturn produces a field control signal 220 identifying the ROI. The fieldcontrol signal 220 is received by the image selecting circuitry 202,which generates a region of interest signal 216 in accordance with thefield control signal 220.

Preferably input 206 enables a user to select preset standard endoscopicviewing angles and instructs the image control circuitry to generate afield control signal in accordance with that selection. It is preferablethat the input 206 enables the user to select viewing anglescorresponding to 0, 30, 45 and 70 degrees relative to the longitudinalaxis of the endoscope.

It is also preferable that input 206 also provides a user with a nudge,or progressive adjustment, capabilities. In such an embodiment, input206 can provide a selection 218 that incrementally alters the ROI suchthat the user can see a portion of a cavity just outside the field ofview for the viewing angle. In one aspect, the input can provide aselection 218 that incrementally adjusts the viewing angle in thelongitudinal direction above or below the current viewing angle,shifting the pixels selected to form the ROI signal. Alternatively, theinput can provide a selection 218 that incrementally expands the area ofthe ROI in one longitudinal direction by incorporating additional pixelsthat reside in that direction in to the ROI signal. Another alternativeis to for the input to provide a selection 218 incrementally expands thearea of the ROI in both longitudinal directions by incorporating pixelsthat longitudinally reside above the original area of the ROI andincorporating these pixels into the ROI signal. Giving a user theability to nudge enables the user to look slightly beyond what iscurrently shown in the ROI. Today surgeons using a fixed angle endoscopesometimes operate on the edge of the view field with limited visionbecause the endoscope cannot be manipulated to achieve the necessaryview. Slightly changing the orientation of a fixed angle endoscope orswapping one endoscope for another with a different viewing angle can becumbersome and dangerous. By incorporating a nudge feature, the user isable to start from a standard endoscopic viewing angle and slightlyshift the viewing angle to see what is outside the initial ROI. Also, ifa preset view angle does not provide the necessary field of view,changing to another preset viewing angle will require the surgeon toreorient themselves. The nudge enables the surgeon to make a progressivechange to the viewing angle and helps avoid disorientation.

Typically when a user switches between standard endoscopic viewingangles the user can become disoriented because the placement of commonobjects within a body cavity at the second viewing angle will differthan the first viewing angle. To address this problem, it is preferablethat input 206 enables a user to rotate an image formed within a ROI. Insuch an embodiment, input 206 can provide a selection 218 to imagecontrol circuitry 204 to generate a field control signal 220 thatinstructs image selecting circuitry 202 to rotate the image produced bythe region of interest signal 216 about the viewing angle axis. Thisembodiment enables a user to electronically correct the orientation ofan endoscopic image in order to overcome any problems associated withdisorientation.

The endoscopic system further includes video processing circuitry 208that converts the region of interest signal 216 and/or image signal 214into a video signal 222, which is received by a standard display 210.When the video processing circuitry 208 receives image signal 214, theprocessing circuitry generates an all image video signal. When the videoprocessing circuitry 208 receives ROI signal 214, the processingcircuitry generates a region of interest video signal.

FIG. 4A shows an embodiment of the image generated by video signal 222on display 210. Display 210 provides a video image 280 that includes afirst frame depicting the region of interest image 180 for a selectedviewing angle, in this case 45 degrees, and a second frame that displaysthe all image video signal 270. It is preferable that the all imagevideo signal 270 also include indicia 185 that show the location of theregion of interest image 180 relative to overall field of view. Videoimage 280 is beneficial because in most surgical situations it is usefulfor the surgeon to have the largest view of the entire field possible.However, as discussed below, very large fields of view can be subject tosignificant distortion and are not always optimal to use for surgicalvisualization. When a large field 270 is coupled with a local view 180associated with a ROI, it becomes useful because it helps the surgeonsee where the selected ROI 180 is located in the global surgicallandscape. FIG. 4B shows an alternative display scheme using a largemonitor 290 which displays a global image 270 and simultaneously a fullscale local image 180 on top of the global image.

In typical wide angle systems, the information density will vary acrossthe captured field, i.e. for viewing angles that are further away fromoptical center 160, such as the 0 and 70 degree viewing angles depictedin FIG. 2A, the information density can be substantially less thanoptical center. When such a wide angle field of view is projected on toa solid state imager, such as a CCD or CMOS imager, the resolution ofthe field at these viewing angles can be noticeably poor. As shown inFIG. 3A, the information density across image surface area 170 istypically greater towards the center of the imager and can decreasesubstantially across the imager in the longitudinal directions. Whilethe present invention can be implemented without adjusting for thisdifference in information density, it is preferable that endoscope 10provide a transmission system 150 that redistributes the image field toeven out the information density across image surface area 170. To evenout the information density and improve the resolution of the imager asshown in FIG. 3B, it is preferable that transmission system 150 comprisean f-theta optical system. An f-theta optical system uniformly separatesthe image rays incident to wide angle lens 165 by a distanceproportional to f-theta, where f is the focal distance of the lenssystem and theta is the angle of incidence of the image rays relative tooptical axis 160. The f-theta optical system provides a uniformredistribution of the image field relative to the optical axis such thata more uniform information density can be provided on the imaging area.

If the optical system does not correct the variation in informationdensity attributable to the wide angle lens system, then it may benecessary to provide circuitry that can correct any distortion or uneveninformation density that can be present in the image signal or theregion of interest signal. However, by utilizing an f-theta opticalsystem, the need to incorporate corrective circuitry and thecomplexities associated with such manipulation can be avoided.

The present invention merges the versatility of mechanical variable viewsystems with the relative simplicity of solid state designs. Theadvantage of the present invention is that it provides a variable viewsystem that reduces or eliminates the need to use complex mechanicalsystems. The present invention also overcomes a number of disadvantagesprovided by typical wide angle endoscopic systems that incorporate solidstate imagers. The present invention can provide a single instrumentwith no moving parts which provides the surgeon with all the standardand familiar viewing directions and ergonomics while maintainingexcellent imaging performance.

The present invention has been described above in terms of a presentlypreferred embodiment so that an understanding of the present inventioncan be conveyed. However, there are alternative arrangements for a solidstate variable direction of view endoscope. The scope of the presentinvention should therefore not be limited by the embodiments discussed,but rather it should be understood that the present invention is widelyapplicable to variable viewing direction instruments in general. Allmodifications, variations, or equivalent elements and implementationsthat are within the scope of the claims should therefore be consideredwithin the scope of this invention.

What is claimed is:
 1. An endoscope, comprising: a wide angle lenssystem that includes an optical axis that is angularly offset from alongitudinal axis of the endoscope such that the optical axis resides atan angle greater than zero degrees to the longitudinal axis, wherein thewide angle lens system simultaneously gathers an endoscopic image fieldat least spanning the longitudinal axis and an angle greater than ninetydegrees to the longitudinal axis; a solid state imager having an imagingsurface area that receives at least a portion of endoscopic imagetransmitted by the wide angle lens system and produces output signalscorresponding to the endoscopic image field; image forming circuitrythat receives the output signal and produces an image signal; and animage transmission system resides in the transmission path between thewide angle lens system and the imager, the image transmission systemhaving at least one lens that alters the distribution of the endoscopicimage field to correspond to the imaging surface area such that thedistribution of the endoscopic image field on the imaging surface areahas a uniform information density, wherein the at least one lensdistributes substantially the entire endoscopic image field in thelongitudinal direction to correspond to the imaging surface area, andwherein the image transmission system includes an f-theta lens system.2. The endoscope of claim 1, wherein image selecting circuitry thatreceives the image signal and produces a region of interest signal thatcorresponds to a region of interest field that is less than theendoscopic image field.
 3. The endoscope of claim 2, wherein the regionof interest field corresponds to a standard endoscopic viewing angle. 4.The endoscope of claim 3, wherein the standard endoscopic viewing angleis selected from a group consisting of zero, thirty, forty-five, andseventy degrees.
 5. The endoscope of claim 2, further comprising imagecontrol circuitry that receives a region of interest field selectionfrom a user input and produces a field control signal identifying theregion of interest field, wherein the image selecting circuitry receivesthe field control signal and produces the region of interest signal inaccordance with the field control signal.
 6. The endoscope of claim 5,wherein the user input enables a user to select at least one presetstandard endoscopic viewing angle and instructs the image controlcircuitry to generate a field control signal in accordance with thatselection.
 7. The endoscope of claim 6, wherein the user input enables auser to select a progressive adjustment and produces an adjustmentsignal that incrementally alters the region of interest.
 8. Theendoscope of claim 7, wherein the adjustment signal incrementally altersthe viewing angle above or below the at least one preset standardendoscopic viewing angle.
 9. The endoscope of claim 7, wherein theadjustment signal incrementally increases the area of the region ofinterest in at least one longitudinal direction.
 10. The endoscope ofclaim 7, wherein the adjustment signal incrementally increases the areaof the region of interest in two longitudinal directions.
 11. Theendoscope of claim 5, wherein the user input enables a user to rotatethe image formed by the region of interest signal.
 12. The endoscope ofclaim 2, wherein the image selecting circuitry rotates the image formedby the region of interest signal.
 13. The endoscope of claim 2, whereinthe image selecting circuitry rotates the image formed by the region ofinterest signal about the axis of the viewing angle.
 14. The endoscopeof claim 1, further comprising video processing circuitry that generatesvideo signals on the basis of the image signal and outputs the videosignal to a display.
 15. The endoscope of claim 14, wherein the videoprocessing circuitry generates an all image video signal based on theimage signal and outputs the all image video signal to the display. 16.The endoscope of claim 15, wherein the video processing circuitrygenerates a region of interest video signal based on the region ofinterest signal and outputs the region of interest video signal to thedisplay.
 17. The endoscope of claim 16, wherein the video processingcircuitry generates a combined video signal having a first framedisplaying the region of interest video signal and a second framedisplaying the all image video signal.
 18. The endoscope of claim 17,wherein the second frame includes indicia denoting the local region ofinterest corresponding the all image video signal.
 19. The endoscope ofclaim 1, wherein the image surface area is rectangular and has alongitudinal dimension that is aligned with the longitudinal dimensionof the endoscopic image field.
 20. The endoscope of claim 1, furthercomprising an HD image sensor.
 21. An endoscope, comprising: a wideangle lens system that includes an optical axis that is angularly offsetfrom a longitudinal axis of the endoscope such that the optical axisresides at an angle greater than zero degrees to the longitudinal axis,wherein the wide angle lens system simultaneously gathers an endoscopicimage field at least spanning the longitudinal axis and an angle greaterthan ninety degrees to the longitudinal axis; an imager having animaging surface area that receives at least a portion of endoscopicimage transmitted by the wide angle lens system and produces outputsignals corresponding to the endoscopic image field; image formingcircuitry that receives the output signal and produces an image signal;and an image transmission system resides in the transmission pathbetween the wide angle lens system and the imager, wherein the imagetransmission system redistributes the image field to even out theinformation density across the imaging surface area.
 22. The endoscopeof claim 21, wherein in that the image transmission system having anf-theta lens system.
 23. The endoscope of claim 21, wherein the imagetransmission system has at least one lens that alters the distributionof the endoscopic image field to correspond to the imaging surface area.24. The endoscope of claim 23, wherein the at least one lens distributessubstantially the entire endoscopic image field in the longitudinaldirection to correspond to the imaging surface area.
 25. The endoscopeof claim 21, wherein in that the at least one lens distributessubstantially the entire endoscopic image field in the longitudinaldirection to correspond to the imaging surface area.
 26. The endoscopeof claim 21, wherein the imager is a solid state imager.
 27. Theendoscope of claim 21, wherein the imaging surface area is square,circular or oval.
 28. The endoscope of claim 21, wherein the imagingsurface area has an HD aspect ratio of 16:9.